http://lifehacker.com/your-android-phone-has-a-built-in-childproofing-feature-1794809851 Useful feature for forcing an app to stay in the foreground without accidentally clicking off and going to the homescreen. Whilst intended for (weak) childproofing, it’s useful when you’re playing Ingress and running at the same time (like me), often knocking the buttons and either clicking the menu button, back button or home button.